How To Fully Delete All Personal Data And Other Files On Your Laptop Computer. Hard Drive Encryption Can Help As Well

Encryption can do the same job with the added benefit of protecting data if your device gets stolen

So you’re selling your computer. Or it’s so old that you have to toss it away. But you’ve also read how discarded computers can lead to identity theft. How’s that work, anyway? And what can you do to prevent it from happening? The answer lies in how much time you have. I’d personally use encryption software like hard drive encryption software, since it makes things a little easier and convenient, but you may not find it applies to you at this stage.

Deleting Data: Data Cannot Be Deleted

The secret about data deletion is this: data cannot be deleted, only replaced. You’ve read how computers store data in patterns of 1’s and 0’s, which are also known as bits. When you click on “empty recycle bin” on your computer’s desktop, all those bits remain in place. What you’ve “deleted” by emptying the recycle bin is the instruction set the computer uses to find those bits: the 1’s and 0’s are still there, it’s just that the computer doesn’t know where to look for them. If you will, it’s like a bank losing its accounting books. The money is still in the bank, but the bankers don’t know how much belongs to whom. Pandemonium ensues.

The implication is that, if given the right software, “deleted” data can be uncovered. Actually, it’s more than an implication. I know I bought Norton Disk Doctor back in the 90’s specifically because it allowed me recover files I deleted accidentally, so the technology to recover deleted data has been around for decades.

Overwriting Data Takes Forever

As you can conclude from the above explanation, when experts say that data should be deleted prior to computers being sold or recycled, what they really mean is that data should be overwritten. Turn those sequences of 1’s and 0’s entirely to 1’s, for example. What most overwriting software will do is randomly generate bits and write that to your hard drive. Since those bits are random, they don’t represent any information. More importantly, two bits can’t share the same space, so the randomly generated data (new) replaces the original data (old).

The problem with data overwrites is that it takes time and, because every single bit has to be replaced, the bigger your computer’s hard drive, the longer it takes. It’s not unusual to see a computer chugging away at this task for 10 or more hours when it comes to 100 Gb hard drives.

Plus, it’s understood that one pass is not enough. The Department of Defense, for example, requires that three passes be done per disk. Some advocate 35 passes! This is because a study found anything less increased the chances of someone being able to glean data in your drives. Thirty-five passes is, however, not necessary. Even the original author of the study has called it overkill for most people.

Fujitsu Can Delete Your Data In Seconds

Yep, you read it right. I’ve just told you that it takes time to overwrite data, and yet here’s a Japanese company that claims otherwise. It’s because their new hard drives will be using AES-256 encryption. They can make their claim because all they have to do is destroy the encryption key, which does take only seconds to destroy. And since encryption protects data by randomizing bits and bytes (the same type of randomizing that goes on when overwriting data), Fujitsu’s in the clear with such a claim.

The only problem? These hard drives are not available until sometime next year. So, until then, you’ll have to do data overwrites when disposing of your old computer.

However, Fujitsu does bring up an interesting point: what would you prefer, having to spend hours of extra time prepping a computer just so you can dispose of it, or spending seconds only? Remember, there is the added benefit that drive encryption software will protect your data while you’re using the computer.

If you’re concerned about data security the choice is obvious. Again, the bad news is that these falutin’ drives won’t be available until next year. However, if you’re really looking to protect your sensitive data, then you have the option to encrypt your data today. Encryption as a service is available from companies like AlertBoot, and make encryption a snap. And, such encryption software is not just for computers. If you’ve got external hard drives, you’ll probably want something that will do usb disk data security as well.

Of course, encryption doesn’t make sense if you are looking to dispose of your old computer today, like, right now. But, it’s something you should keep in mind for when you get your new computer.

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About sang_lee

Sang Lee is a Senior Account Manager and Security Analyst with AlertBoot, Inc., the leading
provider of managed endpoint security services, based in Las Vegas, NV. Mr. Lee helps with the deployment and ongoing
support of the AlertBoot disk encryption managed service.
Prior to working at AlertBoot, Mr. Lee served in the South Korean Navy. He holds both a B.S. and an M.S. from Tufts
University in Medford, Massachusetts, U.S.A.